The implication is that border security is futile and often counterproductive. This was made even more clear in their silly video that accompanied the piece that opened with a man with his face blacked out (presumably a human smuggler) saying "You can keep trying, but usually the people who want to get across to the states, they will get across the states." Then the narrator says "There is one guaranteed way to get across on your first try: a corrupt border official wiling to take a bribe."
Here are the names of all the corrupt agents discussed in the piece: Raul Villarreal, Fidel Villarreal, Luis Alarid, Jose Olivas Jr., Jose Ramiro Arredondo, Miguel Angel Avina, Juan Luis Sanchez, Jose Magana, Luis Francisco Alarid, and Michael Gilliland.
As evidenced by the last-named, white officers are certainly capable of corruption, but Latin America has notoriously corrupt law enforcement and we seem to be importing their problems by putting the fox in charge of guarding the hen house.
Of course there are honest Hispanic Agents who do their jobs like Ramos and Compean, and look how they get thanked.